export audio sélectionné impossible

Hello, the function to export the selected audio is grayed out. How to export the selection made with the arrows. I said that I stopped the reading and that I worked audacity 2.3.2 on 64-bit Ubuntu 18.04.03 LTS. Thanks in advance and sorry for my bad english because I’m french

Ensure that some audio is selected, like this:

Note that to make a selection with the mouse, you must click and drag on the track waveform, not on the Timeline above the waveform.
More information here: https://manual.audacityteam.org/man/audacity_selection.html

It’s working now. I made my selection from the rule with time measurements. The selection arrows were displayed, which deceived me. I will deepen the tutorial, thanks for the infos

Selecting in the Timeline is used for the “Quick-Play” feature: https://manual.audacityteam.org/man/timeline.html#tqp